In an Long Term Evolution Advanced (LTE-A) system, to improve spectral efficiency, Multiple-user Multiple-Input Multiple-Output (MU-MIMO) processing may be performed on data streams. That is, a base station may simultaneously transmit data to multiple User Equipment (UEs), or simultaneously receive data transmitted by multiple UEs, and these UEs reuse a same time-frequency resource. In this case, the user equipment performs channel estimation by using a Demodulation Reference Signal (DMRS) in a downlink reference signal, so that the UE successfully demodulates the data.
In a current 3rd Generation Partnership Project (3GPP) LTE-A standard, a DMRS design scheme supporting eight data streams occupies 24 REs, where orthogonal cover code for DMRS code division multiplexing of every four data streams is 4. The base station sends DMRSs by using eight DMRS ports. After receiving DMRS messages, the UE obtains channel estimation according to the DMRSs, so as to demodulate data.
In a process of implementing the foregoing data processing, the prior art has at least the following problem. When a large-scale antenna system can support more than eight data streams, the base station sends DMRSs in a non-orthogonal manner, so as to reduce time-frequency resources occupied by the DMRSs. Because the base station sends the DMRSs in the non-orthogonal manner, interference between the DMRSs is relatively large, and therefore accuracy in channel estimation performed by a user is reduced.